TITLE:   GCN CIRCULAR
NUMBER:  40294
SUBJECT: GRB 250430A: Kanata optical upper limit
DATE:    25/04/30 18:52:29 GMT
FROM:    Koji Kawabata at HASC,Hiroshima U <kawabtkj@hiroshima-u.ac.jp>

K. S. Kawabata, T. Hori, T. Nakaoka (Hiroshima Univ.) report on 
behalf of Kanata team:

We performed optical imaging polarimetry to the field of the
GRB 180720B (Parsotan et al. GCN 40292; Lipunov et al. GCN 40291) from
2025-04-30 17:34:03 UT (162 seconds after the trigger) with HONIR 
attached to the 1.5-m Kanata telescope at Higashi-Hiroshima Observatory,
Japan. We did not detect any new optical source up to a limiting 
magnitude of Rc = 16.0 (3-sigma; Vega mag) at the position of the UVOT
source in our first 30 second exposure.